Here’s some links you might find helpful or informative

Turntables:

• Components of a Turntable
• Guide to Phono Stages
• How to Set Up a Turntable
• How to Install and Calibrate a Turntable Cartridge
• How to Purchase a Used Turntable

Analog Tape and Recorders

• Tape Info Table
• Response Curves of Analog Recorders

Mods

• Marshall Class 5

Technical Stuff

• Op Amps: Myths & Facts
• Op Amp Measurements
• Spring Reverb Tanks Explained and Compared
• Using Op-Amps to Interface to Spring-type Reverb Units